Shipping tube with integral end closure



23, 1954 J. c. BAXTER ETAL 'SHIPPiNG TUBE WITH INTEGRAL END CLOSURE Filed March 24, 1950 FIG. 3

INVENTORS e s C-fidxtc r' T ORNEYS Patented Feb. 23, 1954 I WITHYTNTEGRAEEND CLOSURE James lbBaktergMinerva, andJohn Hi French,

. ...Beloit, Ohio 1 hpplicatioh March 24, rssos's'efial Nai -15137 58 -11 Claims. 1 Thisinvention relates tb shipping .t'ubes' and particularly to mailing tubes formediofeflexible -:-.=--=and resilient material 'such as paperboard.

The inventionhas foran object'toprovide a 'shipping' tube of cylindrical or other generally wround form with integral closure flaps at an end thereof that are formed tointerlock and provide v a strongclosure for the end of the-tube.

A further'object of the invention is to'provide a closure that'comprises a pair of flaps that are integral-with diametrically opposite quadrants of the tube and that have tongues and slots which :"provide an interlock tosecu'rely hold the flaps substantiallyperpendicular to the axis of-the tube and in lapping relation across the end of the tube.

An additional object of theinvention is to prowide a closure that is formed. by two superim- --posed pairs of interlocked flapsintegral with the cylindrical body of the tube.

It is also an object of the invention to provide the ends of the tube with closure flaps that are of a: width slightly less than the diameter of the tube and which are so connected to the body (ii -the tube that "they can readily be bent totube closing position.

With the above and other objects in view,

the"invention may be said to comprise the shipffping tube as illustrated in'the accompanying drawings and hereinafter described, together with such modifications" and: variations J thereof as will'be'apparent to one skilled in the" art to 1"which the invention pertains.

j'fReferenceshould be'had' to the accompanying 'g'drawings forming apart of this. specification, in

which:

Figure 1 is a perspective view of a shipping tube embodying the invention;

Fig. 2 is a fragmentary transverse section through an end closure taken on the line indicated at 2-2 in Fig. 1;

Fig. 3 is a side elevation of the tube showing the closure flaps in their open positions in which they are extensions of the cylindrical body of the tube;

Fig. 4 is a fragmentary side elevation of an end of the tube showing one pair of flaps interlocked in tube closing position and the other pair of flaps extended;

Fig. 5 is an end elevation of the tube with the flaps interlocked in closed position, the underlying portions of the top flaps being shown in dotted lines; and

Fig. 6 is a plan view showing the end of the tube flattened and die cut to form the closure flaps.

f athei accompanying drawings "thez invention is shcwntappliedistoi a paperboardsxmailinge tube 11 of i cylindrical formwhich is I provided :with Jfourflaps 2- at-each of its endsthatarea-integi'al 5' with the body of the tubeg-andzthat are formed tointerlock' across the ends of .-the: tube -to'-tproi t'i'deiend closures; Each flap is of-a size'to mover the major portion of the end openingwof tthe atube' and has onelongitudinal'sid'ei'edge 3 :tliat is 10 parallel to the'axis of" thetube throughoutsthe m'aj'or portion of-the length'ofthevtube.

' On the side thereofsopposite. the straightwedge 3;' 'each' flap 2 has a lateral slotfds'providedc with a flaring --end' 5. opening to :the @sidev edge ofcthe l5 flap. Eachslot "4 'extends lsubstantially :totnthe on'gitudinal center line: 1 of the snap"; and thee-innen portion ofi the "slot pr'eferably curvescoutwar-(11y toward the; frees end of I theaflap: toirprovide a --'hoo-kshaped locking tongue '6 .=:between. he 'slot' l' andtheeuter-end of thee-flap l he (fly- 1351 131011 OTi GEGh -flaQThaS' a straightnedge I inwardly of: the slot 4 on the 'side llhBI'QOi-i cpposite the edge 3 and an inset edge 81 outwardly of th 'slot'4 the side edgeportion'8aforrning the 2'5' -outer end ofthe lo'cking tongue 6. v

' The p'ortion of -the flapi"betweenrtheistraight edge' 't and the inner end of :the slot 4* isccontinuous fror'n the base to r the outerzien'd thereof and diametrically opposite flapsi are adapted to 0' be' -interlocked' by passing the locking-tongues "through the slots 4, so as to cause the continuous portion of each flap to ex'tendthroughcthesslct 4 of the diametrically opposite flap and -the lock- "--*ing tongue of each flap to engage the continuous 3'5"""p'ortion of the other flap." When iinterlockedithe "tongueof each flap preferably underliesithe body portion of the diameterically opposite flap as shown in Figs. 1 and 2 of the drawings. In order to enter th locking tongue of one flap into the 40 slot of the other, the flaps are bent laterally enough to allow the locking tongue of each flap to enter the lateral slot of the opposed flap, and after the locking tongues have passed through the slots, the flaps due to their resiliency and 5 that of the tube spring back into alinement and interlock as shown in Fig. 1.

The length of each of the flaps 2 is slightly less than the diameter of the tube but enough greater than the radius of the tube to provide looking tongues of substantial width. In order to accommodate the ends of the flaps within the cylindrical wall of the tube, each flap has a rounded corner 9 at the outer end of its straight edge 3 and a rounded corner ID at the outer edge of the tongue 6.

In order to facilitate the bending of the flaps at the ends thereof that are integrally connected to the cylindrical tube, notches l i are provided at the base of each flap to provide a connecting portion of less width than the body of the flap and more readily bendable.

The end closure structure is preferably formed by a simple die cutting operation. The cutting is performed by a single stroke of a suitable die acting upon the end of the tube when it is flattened out and that has a cutting edge that con forms to the contour of the flaps as shown in Fig. 6 of the drawings. The die is formed with a continuous cutting edge that conform to the margin of a straight axial slot 12 centrally of the flattened portion to form the straight edges 3 of adjacent flaps and the notches H at the inner ends of the edges 3, the rounded corners 9 and I0, edges 1 and 8, notches H and slots 4. The cutting away of folded edge portions of the flattened tube forms two diametrically opposite tapered axially extending slots l3 midway between the slots 12. After the cutting operation the tube springs back to cylindrical form and each of the four substantially identical flaps 2 forms a continuation of one of the quadrants of the cylindrical tube, the flaps being separated by the axially extending slots 12 and i3.

The interlocking tongue and slot connection between each of the two pairs of closure flaps provides a very strong end closure since the axial thrust of articles within the tube is resisted by the interlocking flaps which are placed under tension by such thrusts. The tension imposed upon the flaps is exerted through the continuous edge portions of the flaps which extend through the slots 4 and resisted by the inner ends of the locking tongue 6 which are seated in the ends of the slots 4. While a single pair of opposed flaps forms a strong closure, it is preferred to employ two sets of superimposed interlocking flaps which form a multi-layer end closure of great strength.

It is to be understood that in accordance with the provisions of the patent statutes, variations and modifications of the specific devices herein shown and described may be made without departing from the spirit of the invention.

What we claim is:

1. A shipping tube of cylindrical form having four substantially equiangularly spaced axial slots of substantially equal length extending inwardly from an end thereof to provide four end closure flaps each of a width but slightly less than the arcuate width of a quadrant of the cylinder, two of said slots being diametricallyv opposite one another and opening to slots extending circumferentially from opposite sides thereof to adjacent the longitudinal center line of each flap to provide a laterally extending locking tongue on the outer end of each flap.

2. A shipping tube of cylindrical form having four substantially equiangularly spaced axial slots of substantially equal length extending inwardly from an end thereof to provide four end closure flaps each of a width but slightly less than the arcuate width of a quadrant of the cylinder, two of said slots being diametrically opposite one another and provided with flaring outer ends, lateral slots extending circumferentially from opposite sides of said flaring slots to substantially the longitudinal center line of each flap and having flaring ends opening to the axial slots, said lateral slots providing a laterally extending looking tongue on each flap adapted to be passed through the lateral slot of a diametrically opposite flap.

3. A shipping tube of cylindrical form having four substantially equiangularly spaced axial slots of substantially equal length extending inwardly from an end thereof to provide four end closure flaps, each of said slots having a widened inner end to provide each closure flap with a connection to the tube body narrower than the body of the fiap, two of said slots being narrow slots and of substantially uniform width throughout the major portion of their length and the other two of said slots being diametrically opposite and having flaring outer ends, each flap having a lateral slot opening to one of said flaring slots and providing a laterally extending locking tongue at the outer end of the flap adapted to be passed through the lateral slot of a diametrically opposite flap to lock the flaps together and across the open end of the tube.

JAMES C. BAX'I'ER. JOHN H. FRENCH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 797,175 Collenburg Aug. 15, 1905 880,952 Yarnall Mar. 3, 1908 1,164,153 Woods Dec. 14, 1915 1,745,341 Schoettle Jan. 28, 1930 1,904,365 Geist Apr. 18, 1933 2,189,436 Rosenfield Feb. 6, 1940 2,213,499 McCaskey Sept. 3, 1940 2,235,800 Daly Mar. 18, 1941 

